Organic EL display devices including an organic light emitting diode (OLED) which uses organic electroluminescence (EL) are splendid in power consumption, lightweightedness, thinness, moving picture characteristic and viewing angle characteristic. Recently, organic EL display devices have been actively developed and put into practice.
As organic EL display panels for providing color display, the following two types of organic EL display panels are known (see, for example, Patent Document 1: Japanese Laid-Open Patent Publication No. 2005-85683; and Patent Document 2: Japanese Laid-Open Patent Publication No. 2011-35087).
(1) A three color type organic EL display panel in which red (R), green (G) and blue (B) light emitting elements are used as organic light emitting diodes (OLEDs) to provide color display.
(2) A color filter type organic EL display panel in which an organic light emitting diode (OLED) for emitting white light is used and the white light is transmitted through red (R), green (G) and blue (B) color filters to provide color display.
The above-described three color type organic EL display panel has the following problems. One problem is that at least three sub pixels are required for one pixel, which makes it difficult to provide high-definition display. Another problem is that a structure including RGB light emitting elements for providing high-definition display requires costly production facilities in order to obtain sufficient large process margins.
The above-described color filter type organic EL display panel also has a problem that there is a limit to the definition improvement and it is difficult to reduce the cost.
The present invention for solving the above-described problems of the conventional art has an object of providing a display device capable of displaying a high-definition color image easily without using color filters or red (R), green (G) or blue (B) sub pixels.
The above-described and other objects and novel features of the present invention will be made apparent by the description in this specification and the attached drawings.